Method and apparatus for excavating tunnels



OCL 29, 1935. G. J. scHRoEPl-ER METHOD AND APPARATUS FOR EXCAVATING TUNNELS 2 Sheets-Shree?I l Filed April 25, 1954 Geol/gc J Schl/oeper /12 1*(71'5 18 5 Q47 24 waz,

Oct. 29, 1935. G, J, SCHROEPFER 2,018,926

METHOD AND APPARATUS FOR EXCAVATING TUNNELS Filed April 23, 1954 2 sheets-sheet 2 -1C T a lo 52 a@ 2 65 l\ A \\\Y' Geol/5e d Sclxx/oelafel;

Patented oct. 29, 1935 UNITED STATES METHOD AND APPARATUS `FOR EXCA- VATING TUNNELS George J. Schroepfer, St. Paul, Minn. Application April 23, 1934, Serial No. 721,906

2 Claims.

My invention relates to a method and apparatus for use in excavating tunnels in formations such as St. Peter sandstone and the like and particularly to a method and apparatus utilizing the I principle of abrasion for cutting into the sandstone.

An object of the invention resides in providing a method and apparatus by means of which excavation is accomplished through the action of air jets impinging upon the face of the tunnel.

Another object of the invention resides in providing an apparatus in which air is directed over an annular area at the periphery of the face of the tunnel to provide an annular groove forming a core of stone at the center of the tunnel separated from the wall of the tunnel.

A still further object of the invention resides in providing an apparatus having a support carrying one or more nozzles and adapted to be rotated or held stationary, depending upon the number of nozzles employed to cause the air jets to cut the annular groove.

An object of the invention resides in providing means for guiding said support for movement in a direction parallel to the axis of the 'tunnel for giving depth to the annular groove.

A feature of the invention resides in providing a pipe having a reach extending in a direction parallel to the axis of the tunnel and to which the nozzle is attached, said reach being capable of being advanced into the annular groove as the cutting progresses.

An object of the invention resides in installing 3 within the tunnel a track and in providing a truck traveling thereon and carrying the support for the nozzles, said truck serving to guide the nozzles toward the face of the tunnel.

Other objects of the invention reside in the o novel combination and arrangement of parts and in the details of construction hereinafter illustrated and/or described.

In the drawings:

K Fig. 1 is a longitudinal sectional view of the end 45 of a tunnel showing an embodiment of my invention installed therein. A

Fig. 2 is a cross sectional view taken on line 2--2 of Fig. 1.

Fig. 3 is a longitudinal sectional view taken through the hose connection in one of the standards of the invention.

Fig. 4 is a longitudinal sectional View taken through the manifold of the invention.

Fig. 5 is a front elevational view of one ofthe nozzles of the invention.

Fig. 6 is a side elevational view of the structure shown in Fig. 5.

Fig. 7 is a plan sectional view taken on line 'I--l of Fig. 5.

In tunnels built in sandstone and similar earth I5 formations, it is usually necessary in order to render such tunnelsgabsolutely safeand permanent to line the tunnel with reinforced concrete capable of resisting the stresses to which the structure may be subjected. Where a tunnel l0 is excavated in the customary manner and especially when blasting is resorted to, a considerable overbreak in excavation occurs necessitating an undesirable overrun in concrete, both of which unnecessarily increase the cost of the operation. The present invention provides an apparatus by means of which the tunnel may be accurately formed so as to require a minimum amount of excavation and a minimum amount of concrete and also provides an apparatus by means of which 20 the excavation may progress rapidly and with a relatively small amount of labor.

For the purpose of illustrating the application of my invention, I have shown in Figs. 1 and 2 the end of a tunnel 9 having a bore or passageway Iii therein. This tunnel is of circular cross section and the circular wall of the tunnel is indicated at II, While the face or the end of the tunnel is indicated at I2. The earth in which the tunnel is formed is represented by the reference numeral I 3 and for the purpose of illustration is assumed to be sandstone or other similar earth formation which is readily disintegrated by abrasion through the application of a jet of air thereto.

In the tunnel Ill is provided a track I4 which consists of tvvo rails I5 and I6 spiked to ties I1. This track is laid on a roadway I8 formed in the bottom of the tunnel by cutting the lowermost o portion of the circular wall I I of the tunnel down to a level and for a Width sufficient to receive said track. Upon the track I4 are run ordinary cars by means of which materials may be brought to and from the face of the tunnel and by means of which the excavated stone is removed from the tunnel.

My invention utilizes the track I4 and further utilizes a truck I9 which is carried 'by said track. This truck consists of two longitudinal frame members ZI and 22 which have attached to the undersides thereof bearings 23. The bearings 23 journal axles 24 which have attached to them flanged wheels 25 riding on the rails I5 and I 6 of the track I4. The two longitudinal frame serves as a support for a head 28 lcarrying a number of nozzles 29. The shaft 21 is rotatably 'mounted'in bearings 3l and 32 formed on two standards 33 and 34. The standards 33 and 34 are attached to the floor 26 of truck i9 through bolts 35. The shaft 21 is hollow, being formed with a bore 36 into which air under pressure is directed and by means of which the various noz- Y Y zles 29 are fed with air.

The head 28 comprises a manifold 38 which is shown in detail in Fig. 4. Thisemanifold consists of ak casting 39 cylindrical in form `,l'iaving a peripheral wall 4I Vand radial walls 32 rand 43. A boss te issues centrally from the radial wall 43 and is threaded to screwupon the threaded end 45 'of the shaft 21. into the boss 44 holds the manifold 38 from movement on the shaft21. The manifold 38 is formed with a chamber 46 within the same, which chamber communicates with the bore 33 in shaft 21.

'The head 28 further includes a number of arms 46 which are Vconstructed from pipe and which are screwed into bosses e9 equally spaced about the periphery of the wall 4I. These arms extend outwardly toward the wall I I of the tunnel I9 and are formed with bends 5i providing longitudinal reaches 52 arranged in the form of a circle or cylinder having a diameter slightly less than thediameter of the tunnel proper. The shaft 21 is arranged with'its axis coincident with the axis Qflthetunnel lso thatthe head 28 may rotate free/ly within the `bore of the tunnel. 'Ihe various nozzles 29 are attached to the reaches 52. For the purpose of reinforcing the arms 48, braces 53 areemployed, which braces may be constructed of pipe or any other suitable material kand are welded to the arms 48. The manner of arranging these braces is clearly shown in Fig. 2.

In addition tothe nozzles 29 which are arranged about the periphery of the head 28 a cen- Vtrally located nozzle 54`is employed which is attached to a pipe 55 coaxially disposed relative to shaft 21. This pipe is screwed into a boss 56 formed on the manifold 38 and also communicates with the chamber i6 within said manifold.

Y im

Thefvarious nozzles 29 are similarly constructed and are shown in detail in Figs. 5, 6 and 7. These nozzles are each provided with a body 51 having a boss 5SA formed thereon and threaded upon Vthe threaded ends59 of the various reaches 52 of arms Y 413. These nozzles are further constructed with a tip 6I angularly disposed with respect to the boss 58. This tip is elongatedin form and Vis provided rwith a row of orifices 62 whichextend Y through saidtip and communicate with a chamber 63'within .the nozzle proper. By means of the particular arrangement of orinces andthe inclination of the nozzle as shown, propulsion of the shaft `28Y throughthe force of the air leaving the nozzleis partly procured. In addition a progressive application of air to the area to be cutorabraded is procured. Y 1

Air under pressurev is directed into the bore 36 of shaft 21 through a hose 64 shown in Fig. 1.

The manner of vconnecting thishose is illustrated detail in'FigB. The end 95 ofthe shaft 21is Yslightly reduced in diameter and is journaled in` V the bearing 32 previously referred to. This shaft projects Voutwardly beyond theend of the saidy bearing. At such locality the bearing is reduced in .diameteras ,designatedat 66 and is threaded VVto receiye a; cap V61 forming part of a stuiing box A set screw 41 threaded indicated in its entirety by the reference numeral 68. The cap 61 is so constructed. that a packing 69 encircling shaft 21 is forced against the protruding portion of the end 65 of said shaft and a fluid tight connection afforded between the bear- 5 is constructed with a nipple 13 over which the hose 641s applied and which'also communicates with chamber 19. An ordinary hose clarnp'15 is used for holding the said hose applied to the 15 nipple. It will be readily comprehend-ed that airV under pressure may be directed into chamber 19 -within the housing 1I through the hose 64, and from said chamber directed into the bore 36 of shaft .21. Leakage along the bearing V32 is pre-*2o vented by the stuffing box 68. y

Through the angularity of the nozzles r29 Vpropulsion of the shaft .21 may be procured by the air impinging upon the face I2 of the tunnelr proper. However, if desired, positive means mayz be employed for rotating said shaft. In Figs. 1Y andY 2 such construction has been shown. Upon slr-.aft 21 vand in close proximity to the bearing 3| is mounted a spur gear 11. This gear rides against the .bearing 3| andrestrains the shaft 21,30 from axial movement in oneV direction. A collar 19 at the other end of the shaft engages bearing 32 and restrains said shaft from axial movement in the vother direction. The spur gear '11 meshes with a pinion 18 which is secured to apulley 19. 3 5 Both the pinion 18 and pulley 19 are rotatably mounted on a stubshaftV 8| which is secured to a boss 82 formed on standard 33. A belt 84 passes over the pulley 19 and over another pulley 857Qn the end of the armature shaft of a motor 86.40 Motor 96 rests upon the floor 280i truck I9 and is secured thereto in the ordinary manner. By means of this construction; shaft 21 maybe rotated at a greatly reduced rate of speed. i The operation of my invention is'as follows: 45 The truck I9 is run along the track I4 until the nozzles 29 vand 54 are in close proximity to the face I2 of the tunnel. Motor 86 is then turned on which starts rotation of the shaft 21. Air is then directed into the bore 36 of shaft 21 5o through hose 14, which causes air jets from the orifices 62 of said nozzles. These air jets strike the surface of the sandstone and abrade and disintegrate the same, reducing the earth formation to a granular form. `The grains so formed :55 impinge upon the uncut structure and thereby further reduce and cut the rock formation. If the shaft 21 rotates an annular groove 81 is cut bythe nozzles 29 at the periphery of the tunnel, one'wallv of which groove forms'the wall I I of the .69

tunnel proper.Y In addition, a bore 88 is also out l 'through a pinch bar or through any other suitable mechanism which may be connectedV to thewheels o f the truck I9. Y The head 28 is thus advanced toward the face I2 and as the cutting continues l79 reaches 52'travel into Vthe groove 81untilA the .arms 48 are within a short distance of the face of thev tunnel. At 'such time the apparatusis shut down and moved back along the trackV I4. 'Ihe core 89 is then blastedV by means of dynamite fg which is applied to the central bore in the core and to such other bores as may be required. The blast breaks down the core, the brokenstone or muck falling to the floor of the tunnel. Suitable trucks or cars may then be run upon the track I4 and the muck carried away. After the muck has been cleared away, the roadway I8 is extended and a further length of track added to extend the track up to the face of the tunnel a distance sufcient to permit of repeating the operation. The truck I9 is then brought back and the procedure repeated.

In the use of my invention overbreak in excavation is effectively minimized and any undesirable overrun in concrete thereby avoided.A The apparatus is simple and inexpensive in construction and is inexpensive in operation. Thus, with my invention, tunneling operations in sandstone and similar formations are readily and economically accomplished.

Changes in the specic form of my invention, as herein disclosed, may be made Within the scope of what is claimed without departing from. the spirit of my invention.

Having described my invention, what I claim as new and desire to protect by Letters Patent is:

1. The method of cutting a channel in sandstone or the like, which comprises directing against the material a plurality of jets of air in closely spaced relationship and arranged successively lengthwise oi.' said channel, and causing said jets to move as channel, whereby sand particles loosened by a leading jet are, immediately upon being loosened, caught by a trailing jet and caused thereby to eiect an abrading action upon unloosened sand particles in said channel. 10

2. In apparatus of the character described for cutting a tunnel outlining channel in sandstone. an air nozzle supported to move along an area of the tunnel face defining the longitudinal and lateral extent of the channel to be formed, means l5 for moving the nozzle, said nozzle having a plurality of air passageways therein extending in the direction of said area for directing jets of air against the same, said passageways being arranged successively lengthwise of said area and 20 in closely spaced relationship, a trailing jet of air from one of said -passageways being adapted to catch sand particles loosened by a leading jet of air from a preceding passageway and force such particles with abrading effect against unloosened 25 sand particles in said area.

GEORGE' J. SCHROEPFER.

a unit lengthwise of said 5 

